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Very Remote Lisp Debugging Story
- gmfawcett 5y agoDirect link to Ron's story: https://flownet.com/gat/jpl-lisp.html https://flownet.com/gat/jpl-lisp.html ("1994-1999: Remote Agent")
- dang 5y agoPast related threads: Lisping at JPL (2020) - https://news.ycombinator.com/item?id=28113434 https://news.ycombinator.com/item?id=28113434 - Aug 2021 (9 comments) Lisping at JPL (2002) - https://news.ycombinator.com/item?id=22087419 https://news.ycombinator.com/item?id=22087419 - Jan 2020 (307 comments) Lisping at JPL (2002) - https://news.ycombinator.com/item?id=17051503 https://news.ycombinator.com/item?id=17051503 - May 2018 (1 comment) Lisping at JPL (2002) - https://news.ycombinator.com/item?id=13626074 https://news.ycombinator.com/item?id=13626074 - Feb 2017 (37 comments) Lisping at JPL (2002) - https://news.ycombinator.com/item?id=7989328 https://news.ycombinator.com/item?id=7989328 - July 2014 (19 comments) Lisping at the Jet Propulsion Lab - https://news.ycombinator.com/item?id=3773087 https://news.ycombinator.com/item?id=3773087 - March 2012 (1 comment) The rise and fall of Lisp at the Jet Propulsion Lab (2002) - https://news.ycombinator.com/item?id=2212211 https://news.ycombinator.com/item?id=2212211 - Feb 2011 (36 comments) The Rise and Fall of Lisp at the Jet Propulsion Lab. - https://news.ycombinator.com/item?id=304736 https://news.ycombinator.com/item?id=304736 - Sept 2008 (72 comments)
- ncmncm 5y agoOf course similar stories, not involving Lisp, abound. So, this story does not, in the end, reveal any unique merit of Lisp, however fun it is as a story.
- nesarkvechnep 5y agoName a few such stories, besides Erlang related.
- ncmncm 5y agoI don't know of any space probes coded in Erlang. But it would be hard to identify any long-lived space probe whose software was not updated after launch. There are famous stories about Mars rovers.
- p_l 5y agoUpdated, yes. Remotely debugged, no.
- ncmncm 5y agoHow do you suggest they determined what to put in the new version of the software? Rolled dice?
- p_l 5y agoLocal simulations, testing, etc. A REPL is much easier to connect than gdbstub when the link has 20 minute RTT. Remote Agent was first for a) being able to be interactively debugged at remote b) actually exercising that, also c) IIRC it was already designed as basis to provide self-healing kind of ability to the system (or I might be confusing it with another lisp system from Ron Garret while he was at JPL)
- gmfawcett 5y agoHow many of those stories happened before the DS1, though? It's easy in hindsight to say that our new, non-Lisp system better have remote debugging at least as good as the DS1's. That suggests two (possible) unique merits of Lisp: a repl with the full language environment at one's disposal, as an out-of-the-box feature; and, well, being a trailblazer. :)
- rurban 5y agoI was at Ron's conference talk, and I remember it differently. The spacecraft had a problem, but was not allowed to run on lisp. Hence debugging and fixing it in a repl was impossible. But Ron wrote a simulator in lisp, and could verify the necessary procedure in his lisp simu. The C code was patched and the spacecraft survived the reboot. But after re-reading the paper I could have mixed it up, and lisp was indeed in space, and was only killed later. I often remember his story, and often implement similar simus for my firmwares. And very often such a simu is the best tool to find bugs or to verify patches.
- dmytrish 5y agoFor the reference: 100 million miles is slightly more than 1 AU. It means that one-way communication latency is almost 10 minutes, so the round-trip latency is about 20 minutes.